Programs, referred to as "trace" programs, are known for error detection and error localizing in other programs or sub-programs. By means of these trace programs, the execution of a program to be checked is duplicated step-by-step and information resulting therefrom is logged. In addition to this information, respective time information, origin and destination information and information indicating the respective switching-oriented condition are logged. The origin information respectively represents a program by means of which information is formed or to which information is communicated. The destination information identifies the destination program to which the information is communicated.
Upon utilization of such trace programs in communication systems such as, for example, in a switching system, it is predominantly switching-oriented information such as, for example, call set up and cleardown messages, that is logged or registered. The trace programs are predominantly realized as administration and maintenance programs in a communication system, whereby these programs that are not constantly used are transferred or "loaded" into the main memory of the central controller of the communication system as needed from a peripheral storage means that is usually a read-only memory, for example, a hard disk. During and after the one-time or repeated execution of the program or programs to be checked, the logged information is communicated to a peripheral storage means and deposited thereat, for example on a "floppy disk". The deposited, logged information can be subsequently displayed or visualized either at a display means of an operating means allocated to the communication system or at a display means, for example a video screen of a personal computer.
The switching-oriented information to be logged for every program step is usually present in coded, for example binary coded form, and registered as code words and subsequently communicated to a display means and displayed thereat. With respect to the decoding, the allocation to the originating and destination program and the information flow of the switching-oriented information, the displayed information requires a time-consuming interpretation by an operator in order to achieve an evaluation of the logged information.